Namely
This ingredient is REACH (Aquatic Chronic 2) ecotoxic.
Restriction in Europe:
Oxidation dye for hair dyeing.
After mixing under oxidative conditions, the maximum content applied to the hair must not exceed 3.0%.
Wording of conditions of use and warnings :
Must appear on the label: the mixing ratio.
"Hair dyes may cause severe allergic reactions.
Read and follow instructions.
This product is not intended for use on persons under 16 years of age.
Temporary black henna tattoos may increase the risk of allergy.
Do not colour your hair if:
- you have a rash on your face or if your scalp is sensitive, irritated or damaged,
- you've already had a reaction after coloring your hair,
- you've had a reaction to a temporary black henna tattoo in the past."